The Impact of Vitamin D on Autoimmunity: Beyond Bone Health

Happy New Year! As we step into this brand-new year, let's shine a light on the critical role of vitamin D, often overlooked in our ongoing battle against autoimmune issues. During a recent visit to my new doctor, my lab results revealed a deficiency in this essential nutrient. Since then, I've been taking a supplement to ensure my body gets the necessary vitamin D. My doctor flagged the low vitamin D level, especially concerning given my autoimmune disease. Discovering that vitamin D plays a vital role in managing autoimmune conditions was eye-opening for me. Let’s learn more about this vitamin and uncover its importance!

What is Vitamin D?

Vitamin D, also known as calciferol, is unique among vitamins because it functions more like a hormone than a traditional vitamin. Our skin has the ability to produce vitamin D when exposed to sunlight. Specifically, UVB rays from sunlight interact with a precursor in the skin, triggering the synthesis of vitamin D3—a form we'll delve deeper into shortly. However, melanin-rich individuals might produce less vitamin D from sunlight, raising the risk of deficiency. Moreover, limited year-round sun exposure in certain regions can also hinder vitamin D production.

Apart from sunlight exposure, vitamin D can be found in various foods. Fatty fish like salmon and mackerel are sources, along with certain UV-exposed mushrooms. Fortified foods like dairy, orange juice, and cereals also offer vitamin D. In the USA, the recommended daily intake of vitamin D is 600-800 IU per day. Just a tablespoon of cod liver oil holds 1,360 IU, while 3 ounces of sockeye salmon provide 570 IU. Half a cup of raw UV-exposed white mushrooms provides 366 IU. However, research suggests that for many people achieving an optimal vitamin D level often requires supplementation, as relying solely on sunlight and diet may not suffice.

Why is Vitamin D important?

Vitamin D is a linchpin in numerous bodily functions. Its primary task involves aiding calcium absorption, vital for strong bones. Insufficient vitamin D can result in weakened or malformed bones, causing problems such as rickets in children and osteomalacia in adults. Furthermore, it works with calcium to protect adults from conditions like osteoporosis. Besides bone health, vitamin D takes on multiple roles—it reduces inflammation, supports muscle function, bolsters the immune system, and helps regulate blood sugar. Its influence extends to genes that manage cell growth and can be detected in various tissues throughout the body.

I used to think that vitamin D comes naturally from cow’s milk; however this is incorrect. Vitamin D doesn't naturally occur in milk; instead, many countries fortify regular cow’s milk with vitamin D as a preventive measure against rickets and osteomalacia. This fortification practice aims to supplement the diet with this essential nutrient, vital for bone health and overall well-being.

Vitamin D and Autoimmunity

Vitamin D isn't just about bone health—it's important for autoimmune disease health too. Here's why: vitamin D is able to bind to vitamin D3 receptors (VDR) and influence how our genes work. It's as if vitamin D is a director telling immune cells what to do. It can calm down certain types of cells that cause trouble and boost others that keep things in check. Now, when vitamin D doesn't work well because of things like our genes or not enough sunlight, it might play a part in kicking off or making autoimmune diseases worse. That's why fixing vitamin D levels, maybe by taking supplements, could be a game-changer for treating autoimmune conditions. 

A study reported in The BMJ revealed that vitamin D supplementation led to a 22% reduced risk of developing autoimmune diseases compared to a placebo. It also highlighted the potential of vitamin D, combined with omega-3 fatty acids, to act as a protective shield against autoimmune conditions. Furthermore, an extensive review underscored vitamin D's implications in various autoimmune diseases like multiple sclerosis and systemic lupus erythematosus. Another review focused on vitamin D's effects on the immune system and autoimmune diseases, and stressed the correlation between low vitamin D levels and a higher risk of immune-related disorders. These recent findings reinforce the claim that vitamin D plays a pivotal role in autoimmunity.

Studies indicate that when our blood's vitamin D levels decrease, the risk of developing or worsening autoimmune diseases increases. Vitamin D plays a role in reducing inflammation and promoting a more tolerant immune system. Deficiency in vitamin D has been associated with various autoimmune conditions, such as type 1 diabetes and rheumatoid arthritis, influencing how these conditions progress. Therefore, maintaining optimal vitamin D levels could act as a critical defense against autoimmune diseases. While we continue to unravel the finer details, strong evidence supports a substantial connection between vitamin D and shielding us from autoimmune conditions. However, larger randomized studies are necessary to comprehensively grasp the mechanisms involved and identify the optimal levels of vitamin D for immune health.

Decoding Vitamin D: D2 vs. D3 – What Sets Them Apart?

You might be familiar with vitamin D3, but how does it differ from the standard vitamin D? Vitamin D comes in two primary forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). These variants differ in their origins—D2 primarily sourced from plants and fortified foods, while D3 is prevalent in animal-derived sources. Research suggests that vitamin D3 tends to exhibit greater potency, effectively raising and sustaining vitamin D levels in the bloodstream for extended periods compared to D2. While both D2 and D3 can contribute to elevating vitamin D levels, the recognized efficacy of D3 often takes center stage, accounting for its frequent mention and widespread use in supplementation.

Closing Thoughts

Vitamin D deficiency is widespread in the US, notably among Black and Hispanic communities. A study examining vitamin D deficiency in the US population found that between 2001 and 2018, 65.5% fell into the categories of deficiency or insufficiency. Furthermore, the study reported that 89.3% of non-Hispanic Black Americans, 85.8% of Mexican Americans, and 80.4% of other Hispanics experienced some level of vitamin D deficiency or insufficiency.

Research has show that low vitamin D levels are associated with increased risks of death due to various conditions, including cardiovascular events, sudden cardiac death, and cancer. Ensuring adequate vitamin D intake, whether through sunlight, diet, or supplements, remains crucial for overall health and averting deficiency-related concerns.

Wishing you a wonderful 2024 full of wellness, resilience, and progress!

Take good care,
Rebecca

References

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Disclaimer: I am not a healthcare provider, and the information provided in this newsletter is intended for educational purposes only. The content shared here should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult with your healthcare provider or physician for personalized guidance regarding any health concerns or medical conditions.